Magnetic sparator



1968 A. c. scHouw ETAL 3,399,134

MAGNET I C SEPARATOR 2 Sheets-Sheet 2' Filed Oct. 27, 1966 INVENTORS M m w 1 & Mm? .5 r x C. .Rg 5 mm; "a: i?

3,399,134 MAGNETIC SEPARATOR Arthur C. Schonw, Corunna, and James R. Brown, Plymouth, Mich, assignors t Hydromation Engineering Company, Livonia, Mich.

Filed Oct. 27, 1966, Ser. No. 594,967 5 Claims. (Cl. 210-42) ABSTRACT OF THE DISCLOSURE A magnetic separator including a circular tank having a bottom inlet and a top outlet, the bottom inlet being tangential to the side wall of the tank to impart a swirling motion to liquid entering the tank through the inlet, so that the liquid spirals upwardly through the tank. A plurality of electromagnets are supported along the flow path of the liquid by columns which provide collecting surfaces, and the electromagnets, when energized, establish magnetic fields in the flow path of liquid which attracts magnetic particles so that they deposit on the collecting surfaces. The particles are released from the collecting surfaces by reversing the magnetic fields, and the released particles are discharged from the tank through a discharge outlet. The method of the invention includes the steps of flowing a particle containing liquid in an annular path defined by collecting surfaces, and subjecting the flowing liquid to a magnetic field which attracts the magnetic particles to the collecting surfaces. Particles are released from the collecting surfaces by reversing the magnetic field.

Background 0 the invention This invention relates to the separation of'particles from a liquid containing particles, and more particularly, to a method of and apparatus for such particle separation wherein the liquid is swirled around an axis and particles of magnetic material in the liquid are attracted to magnets provided along the flow path of the liquid.

It has been proposed to separate particles from a liquid by swirling the particle-containing liquid around an axis at a high velocity to cause the particles to move to the outside of the liquid body by the action of centrifugal force on the particles. Such centrifugal separators have not been entirely satisfactory for some applications; in particular, the range of particle sizes and densities which can be separated has been unduly limited.

Summary of the invention The present invention proposes to separate particles of magnetic material, such as ferrous particles, from a liquid which is swirled about an axis by providing magnets, preferably electromagnets, along the flow path of the liquid to attract the particles to collecting surfaces which are associated with the magnets. In a particular method embodiment of the invention, magnetic particles are separated from a liquid by the steps of flowing particle-containing liquid in an annular path at least partially defined by a collecting surface, and subjecting the flowing liquid to a magnetic field which attracts the magnetic paarticles to the collecting surface, so that the particles deposit from the liquid on the collecting surface. The velocity of the swirling liquid is controlled to normally sustain the particles in suspension, so that the particles must pass through the magnetic field. Preferably, the magnetic field is generated by reversible electromagnets, and to remove the magnetic particles from the collecting surface, the magnetic field is reversed.

The apparatus of the invention includes a tank having a circular side wall and a closed end at the bottom thereof. The tank has an inlet adjacent the bottom wall which States Patent 0 leads through and extends tangential to the side wall so as to impart a swirling motion to liquid entering the tank through the inlet so that the whole body of liquid in the tank swirls about the axis of the tank. Magnet means, preferably a plurality of electromagnets, are supported along the flow path of the liquid and are preferably supported within two columns; a center column and a periph eral column. The electromagnets are energized to establish magnetic fields which extend radially of the flow path of the liquid, and magnetic particles are attracted to and deposit on surfaces of the columns which contain the electromagnets. The clarified liquid overflows the open top of the tank and is discharged through an outlet. Particles are removed from the tank through an outlet at the closed bottom of the tank. The particles are released from the collecting surfaces by reversing the magnetic fields after the liquid has been drained from the tank.

Accordingly, it is an object of this invention to provide a separator and a method of separation wherein magnetic particles are separated from a body of liquid by the action of a magnetic field.

Another object of the invention is to provide a way of magnetically collecting magnetic particles from a swirling liquid body.

A further object of the invention is to provide a way of releasing particles which have been magnetically collected on a collecting surface.

Another object of the invention is to provide a cooperative arrangement of electromagnets and particle collecting surfaces in a separator tank for attracting magnetic particles to the collecting surfaces with magnetic fields from the electromagnets.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

On the drawings:

FIGURE 1 is an elevational view of a separator tank;

FIGURE 2 is a sectional view of the tank taken along line 22 of FIGURE 1;

FIGURE 3 is a vertical sectional view of the tank of FIGURE 1;

FIGURE 4 is an elevational view of a center column for the tank in which one set of electromagnets are supported;

FIGURE 5 is a top plan view of the center column of FIGURE 4; and

FIGURE 6 is a vertical sectional view of an outer column provided in the tank in which another set of electromagnets is provided.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

As shown on the drawings:

The separator of the invention includes a tank 10 which has a circular peripheral side wall 12 which is open at its top end 14 and closed by a bottom wall 16 at its other end 18. The tank 10 has an inlet 20 which is located adjacent the bottom end 16 of the side Wall 12 and which extends through the side wall from the outside to the inside of the tank. The inlet 20 extends tangentially to the circular sidewall 12 of the tank so that when liquid is introduced into the tank through the inlet 20, the liquid swirls about the axis of the circular side wall 12 and forms a vortex at the axis. The liquid follows an upwardly spiraling path through the tank and ultimately over-flows the top end 14 of the tank into a trough 22 provided about the upper end 14 of the tank. The trough has an outlet pipe 24 through which. the overflowing liquid is discharged from the tank. Particles which are separated from the liquid in the tank are discharged through an opening 26 extending through the bottom Wall 16, the opening normally being closed by a cover 28.. The cover 28 is swung open when particles are being removed from the tank 10.

Supported within the tank are two columns; a center column 30 and an outer column 32. It may be seen in FIGURES 2 and 3 that the outer column 32 is positioned next to the side wall 12 of the tank and extends circularly about the tank. The center column 30 is spaced radially inward from the outer column 32, and both columns are concentric and coaxial with the circular side wall 12 of the tank. The columns are made of non-magnetic material such as plastic, as are the walls of the tank 10. The outer column has two walls 34 and 36 spaced radially from each other, and four electromagnets 38 are supported between these walls about midway up the height of the outer column 32. These electromagnets 38 can be energized to produce magnetic fields which extend substantially radially across the annular space between the center column 30 and the outer column 32. The center column 30 also has two radially spaced walls 40 and 42, and another set of four electromagnets 44 are supported between these walls also about midway up the height of the center column 30. The electromagnets 44 are energized to produce magnetic fields which extend radially across the annular space between columns 30 and 32 in the opposite sense relative to the fields of electromagnets 38, and the fields of the two sets of electromagnets 38 and 44 interfere at the midpoint of the space between columns 30 and 32. Thus, the liquid and particles which fiow in an annular path around the axis of the side wall 12 of the tank i.e. between the columns 30, 32 must pass through the fields of one or the other of the electromagnets 38, 44.

Some of the magnetic particles in the liquid will be attracted by the outer set of electromagnets 38, and other magnetic particles will be attracted toward the inner set of electromagnets 44. The particles which are so attracted deposit, respectively, on the inner wall 36 of outer column 32 and on the outer wall 40 of the center column 30. The particles will coalesce or agglomerate into heavier clusters or groups. It may be noted in FIGURES 4, 5 and 6 that the columns are provided with means for suspending the same inside the tank 10. The center column 30 has a pair of crossed arms 50 and 52 attached to the walls 40 and 42 of the colunm, and these crossed arms are adapted to rest on the top of the trough 22 to support the center columns 30 within the side wall 12 of the tank. The crossed arms 50 and 52 have lips 54 at their ends which fit over the outer periphery of the trough 22. The outer column 32 also has lips 56 which fit over the top end 14 of the side wall 12 to suspend the outer column 32 within and next to the side wall 12 of the tank.

In operation, a liquid containing particles of magnetic material, for example ferrous particles, is introduced into the tank through the inlet 20. The liquid and particles enter the tank tangentially and thus are induced to swirl about the axis of the side wall 12 in an annular pattern defined between the columns 30, 33. The whole body of liquid in the tank swirls about the axis of the side wall 12 and follows an upward spiraling path through the tank to the top end 14 of the tank where the liquid overflows at the end into the trough 22 and flows out the discharge pipe 24.

As the liquid and particles flow through the tank they enter the magnetic fields of the two sets of magnets 38 and 44. Some magnetic particles are attracted by the outer set of magnets 38 and other magnetic particles are attracted by the central electromagnets 44, and these particles deposit, respectively, on surface 36 and 40. Of course, any one particle may be attracted alternatively by the magnets and several such attractions may be necessary to finally move the particle to one of the surfaces. Thus, the liquid which reaches the top end 14 of the tank is clarified by virtue of having the particles removed from it.

When the tank is to be cleaned to remove the collected particles from it, the input stream flowing through inlet 20 is shut off, and the bottom door 28 for the tank is opened to drain all liquid from the tank. The current flow to the electromagnets 38 and 44 is then reversed, so as to reverse the magnetic fields which extend from the electromagnets. By virtue of this reversal of the magnetic fields, the magnetic particles are repelled by the respective magnets and are driven off the surfaces of the center column 30 and the outer column 32, the particles falling to the bottom of the tank where they are exhausted through opening 26 and fall into a collector box (not shown). After the particles have been removed, the door 28 is closed and liquid is again introduced into the tank through inlet 20 to begin a new cycle of operation.

Thus, the invention provides an improved separator wherein magnetic particles are removed from a liquid by attraction to electromagnets, so that the particles deposit on surfaces interposed between the electromagnets and the particle-laden liquid. The particles may be driven olf or repelled from these surfaces merely by reversing the electromagnets, and this greatly facilitates cleaning of the apparatus.

We claim:

1. Apparatus for separating particles of magnetic ma terial from a liquid containing such particles, said apparatus including in combination; means defining a chamber having a circular peripheral wall, said chamber having one closed end and another end opposite said closed end, an inlet leading through said peripheral wall tangentially thereto and adjacent said closed end for causing liquid entering said chamber through said inlet to swirl about the axis of said peripheral wall and form a vortex at said axis, a plurality of electromagnets in said chamber between said ends thereof, means supporting and ositioning one set of said electromagnets about the inner surface of said circular peripheral wall and means supporting and positioning another set of said electromagnets about a circle spaced radially inward from said circular peripheral wall and from said first supporting and positioning means so that said sets of electromagnets are spaced along the circular path of the swirling liquid when the apparatus is operating, said supporting and positioning means having continuous surfaces on which magnetic particles can deposit from said liquid due to attraction of the particles by said electromagnets, said surfaces forming an annular space between said sets of electromagnets through which the liquid flows, said electromagnets being energizable in one polarity to provide a magnetic field extending into said flow path which attracts magnetic particles toward said electromagnets and said surfaces and being energizable in a reverse polarity to release magnetic particles from said surfaces, an outlet through said closed end of said chamber for removal of particles therefrom, and a further outlet adjacent said opposite end for removal of clarified liquid from said chamber.

2. The apparatus of claim 1 in which the opposite end of said chamber is open and said further outlet is of the overflow type wherein the clarified liquid overflows the peripheral wall of said chamber.

3. The apparatus of claim 1 in which said supporting and positioning means for said two sets of electromagnets comprise cylindrical double-walled columns having the electromagnets retained between the double walls thereof.

4. Apparatus for separating particles of magnetic material from a liquid containing such particles, said apparatus including in combination; means defining a chamber having a circular peripheral wall, said chamber having a closed bottom end and an opposite end, first imperforate cylindrical wall means in said chamber coaxial with said peripheral wall and spaced radially inwardly from said peripheral wall of said chamber, said first cylindrical wall means and said peripheral chamber wall having means associated therewith sealing the space between the same from the liquid, a first set of electromagnets supported in said space and spaced circularly about said wall means, second imperforate cylindrical wall means in said chamber coaxial with said peripheral wall and spaced radially inwardly from said first cylindrical wall means so that the space between said first and second cylindrical wall means provides an annular flow path for circular flow of the liquid, means associated with said second cylindrical wall means providing another space within said second wall means sealed from the liquid, a second set of electromagnets supported in said another space and spaced circularly about said second wall means, an inlet leading through said peripheral wall adjacent said closed end of said chamber and communicating with said annular flow path, said inlet extending tangentially to said peripheral wall for causing liquid entering said chamber through said inlet to swirl circularly about said annular flow path while flowing upwardly through said annular flow path, said electromagnets being energizable to provide a magnetic field extending into said flow path which attracts magnetic particles towards said electromagnets to deposit such particles on said cylindrical wall means, an outlet through said closed end of said chamber for removal of particles therefrom, and a further outlet from said chamber adjacent said opposite end thereof for removal of clarified liquid from said chamber.

5. In a method of removing particles of magnetic material from a liquid which contains said particles, the steps of tangentially feeding said particle containing liquid at the bottom of an annular flow path of appreciable height, peripherally confining said liquid in said path between a pair of concentric substantially cylindrical particle collecting surfaces, electromagnetically attracting particles from said liquid to said collecting surfaces as said liquid is confined in said path, and flowing liquid over the upper edge of the outer of said surfaces to remove liquid from said path.

References Cited UNITED STATES PATENTS 1,425,366 8/1922 Chapman 210-223 2,596,743 5/1952 Vermeiren 210222 2,874,839 2/19'59 Rogers 100 X 2,939,583 6/1960 Hett 210-223 3,059,110 10/1962 Japolsky 553 X 2,959,288 11/1960 'Fowler 2l0222 2,979,202 4/ 196 1 Orbeliani 210222 X 3,215,272 11/1965' Sweeney 210512 X 3,305,096 2/1967 Schleiss 210 REUBEN FRIEDMAN, Primary Examiner.

W. S. BRADBURY, Assistant Examiner. 

